1 /****************************************************************************** 2 * 3 * Module Name: dscontrol - Support for execution control opcodes - 4 * if/else/while/return 5 * 6 *****************************************************************************/ 7 8 /****************************************************************************** 9 * 10 * 1. Copyright Notice 11 * 12 * Some or all of this work - Copyright (c) 1999 - 2016, Intel Corp. 13 * All rights reserved. 14 * 15 * 2. License 16 * 17 * 2.1. This is your license from Intel Corp. under its intellectual property 18 * rights. You may have additional license terms from the party that provided 19 * you this software, covering your right to use that party's intellectual 20 * property rights. 21 * 22 * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a 23 * copy of the source code appearing in this file ("Covered Code") an 24 * irrevocable, perpetual, worldwide license under Intel's copyrights in the 25 * base code distributed originally by Intel ("Original Intel Code") to copy, 26 * make derivatives, distribute, use and display any portion of the Covered 27 * Code in any form, with the right to sublicense such rights; and 28 * 29 * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent 30 * license (with the right to sublicense), under only those claims of Intel 31 * patents that are infringed by the Original Intel Code, to make, use, sell, 32 * offer to sell, and import the Covered Code and derivative works thereof 33 * solely to the minimum extent necessary to exercise the above copyright 34 * license, and in no event shall the patent license extend to any additions 35 * to or modifications of the Original Intel Code. No other license or right 36 * is granted directly or by implication, estoppel or otherwise; 37 * 38 * The above copyright and patent license is granted only if the following 39 * conditions are met: 40 * 41 * 3. Conditions 42 * 43 * 3.1. Redistribution of Source with Rights to Further Distribute Source. 44 * Redistribution of source code of any substantial portion of the Covered 45 * Code or modification with rights to further distribute source must include 46 * the above Copyright Notice, the above License, this list of Conditions, 47 * and the following Disclaimer and Export Compliance provision. In addition, 48 * Licensee must cause all Covered Code to which Licensee contributes to 49 * contain a file documenting the changes Licensee made to create that Covered 50 * Code and the date of any change. Licensee must include in that file the 51 * documentation of any changes made by any predecessor Licensee. Licensee 52 * must include a prominent statement that the modification is derived, 53 * directly or indirectly, from Original Intel Code. 54 * 55 * 3.2. Redistribution of Source with no Rights to Further Distribute Source. 56 * Redistribution of source code of any substantial portion of the Covered 57 * Code or modification without rights to further distribute source must 58 * include the following Disclaimer and Export Compliance provision in the 59 * documentation and/or other materials provided with distribution. In 60 * addition, Licensee may not authorize further sublicense of source of any 61 * portion of the Covered Code, and must include terms to the effect that the 62 * license from Licensee to its licensee is limited to the intellectual 63 * property embodied in the software Licensee provides to its licensee, and 64 * not to intellectual property embodied in modifications its licensee may 65 * make. 66 * 67 * 3.3. Redistribution of Executable. Redistribution in executable form of any 68 * substantial portion of the Covered Code or modification must reproduce the 69 * above Copyright Notice, and the following Disclaimer and Export Compliance 70 * provision in the documentation and/or other materials provided with the 71 * distribution. 72 * 73 * 3.4. Intel retains all right, title, and interest in and to the Original 74 * Intel Code. 75 * 76 * 3.5. Neither the name Intel nor any other trademark owned or controlled by 77 * Intel shall be used in advertising or otherwise to promote the sale, use or 78 * other dealings in products derived from or relating to the Covered Code 79 * without prior written authorization from Intel. 80 * 81 * 4. Disclaimer and Export Compliance 82 * 83 * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED 84 * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE 85 * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE, 86 * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY 87 * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY 88 * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A 89 * PARTICULAR PURPOSE. 90 * 91 * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES 92 * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR 93 * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT, 94 * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY 95 * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL 96 * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS 97 * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY 98 * LIMITED REMEDY. 99 * 100 * 4.3. Licensee shall not export, either directly or indirectly, any of this 101 * software or system incorporating such software without first obtaining any 102 * required license or other approval from the U. S. Department of Commerce or 103 * any other agency or department of the United States Government. In the 104 * event Licensee exports any such software from the United States or 105 * re-exports any such software from a foreign destination, Licensee shall 106 * ensure that the distribution and export/re-export of the software is in 107 * compliance with all laws, regulations, orders, or other restrictions of the 108 * U.S. Export Administration Regulations. Licensee agrees that neither it nor 109 * any of its subsidiaries will export/re-export any technical data, process, 110 * software, or service, directly or indirectly, to any country for which the 111 * United States government or any agency thereof requires an export license, 112 * other governmental approval, or letter of assurance, without first obtaining 113 * such license, approval or letter. 114 * 115 *****************************************************************************/ 116 117 #include "acpi.h" 118 #include "accommon.h" 119 #include "amlcode.h" 120 #include "acdispat.h" 121 #include "acinterp.h" 122 #include "acdebug.h" 123 124 #define _COMPONENT ACPI_DISPATCHER 125 ACPI_MODULE_NAME ("dscontrol") 126 127 128 /******************************************************************************* 129 * 130 * FUNCTION: AcpiDsExecBeginControlOp 131 * 132 * PARAMETERS: WalkList - The list that owns the walk stack 133 * Op - The control Op 134 * 135 * RETURN: Status 136 * 137 * DESCRIPTION: Handles all control ops encountered during control method 138 * execution. 139 * 140 ******************************************************************************/ 141 142 ACPI_STATUS 143 AcpiDsExecBeginControlOp ( 144 ACPI_WALK_STATE *WalkState, 145 ACPI_PARSE_OBJECT *Op) 146 { 147 ACPI_STATUS Status = AE_OK; 148 ACPI_GENERIC_STATE *ControlState; 149 150 151 ACPI_FUNCTION_NAME (DsExecBeginControlOp); 152 153 154 ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Op=%p Opcode=%2.2X State=%p\n", 155 Op, Op->Common.AmlOpcode, WalkState)); 156 157 switch (Op->Common.AmlOpcode) 158 { 159 case AML_WHILE_OP: 160 /* 161 * If this is an additional iteration of a while loop, continue. 162 * There is no need to allocate a new control state. 163 */ 164 if (WalkState->ControlState) 165 { 166 if (WalkState->ControlState->Control.AmlPredicateStart == 167 (WalkState->ParserState.Aml - 1)) 168 { 169 /* Reset the state to start-of-loop */ 170 171 WalkState->ControlState->Common.State = 172 ACPI_CONTROL_CONDITIONAL_EXECUTING; 173 break; 174 } 175 } 176 177 /*lint -fallthrough */ 178 179 case AML_IF_OP: 180 /* 181 * IF/WHILE: Create a new control state to manage these 182 * constructs. We need to manage these as a stack, in order 183 * to handle nesting. 184 */ 185 ControlState = AcpiUtCreateControlState (); 186 if (!ControlState) 187 { 188 Status = AE_NO_MEMORY; 189 break; 190 } 191 /* 192 * Save a pointer to the predicate for multiple executions 193 * of a loop 194 */ 195 ControlState->Control.AmlPredicateStart = 196 WalkState->ParserState.Aml - 1; 197 ControlState->Control.PackageEnd = 198 WalkState->ParserState.PkgEnd; 199 ControlState->Control.Opcode = 200 Op->Common.AmlOpcode; 201 202 203 /* Push the control state on this walk's control stack */ 204 205 AcpiUtPushGenericState (&WalkState->ControlState, ControlState); 206 break; 207 208 case AML_ELSE_OP: 209 210 /* Predicate is in the state object */ 211 /* If predicate is true, the IF was executed, ignore ELSE part */ 212 213 if (WalkState->LastPredicate) 214 { 215 Status = AE_CTRL_TRUE; 216 } 217 218 break; 219 220 case AML_RETURN_OP: 221 222 break; 223 224 default: 225 226 break; 227 } 228 229 return (Status); 230 } 231 232 233 /******************************************************************************* 234 * 235 * FUNCTION: AcpiDsExecEndControlOp 236 * 237 * PARAMETERS: WalkList - The list that owns the walk stack 238 * Op - The control Op 239 * 240 * RETURN: Status 241 * 242 * DESCRIPTION: Handles all control ops encountered during control method 243 * execution. 244 * 245 ******************************************************************************/ 246 247 ACPI_STATUS 248 AcpiDsExecEndControlOp ( 249 ACPI_WALK_STATE *WalkState, 250 ACPI_PARSE_OBJECT *Op) 251 { 252 ACPI_STATUS Status = AE_OK; 253 ACPI_GENERIC_STATE *ControlState; 254 255 256 ACPI_FUNCTION_NAME (DsExecEndControlOp); 257 258 259 switch (Op->Common.AmlOpcode) 260 { 261 case AML_IF_OP: 262 263 ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "[IF_OP] Op=%p\n", Op)); 264 265 /* 266 * Save the result of the predicate in case there is an 267 * ELSE to come 268 */ 269 WalkState->LastPredicate = 270 (BOOLEAN) WalkState->ControlState->Common.Value; 271 272 /* 273 * Pop the control state that was created at the start 274 * of the IF and free it 275 */ 276 ControlState = AcpiUtPopGenericState (&WalkState->ControlState); 277 AcpiUtDeleteGenericState (ControlState); 278 break; 279 280 case AML_ELSE_OP: 281 282 break; 283 284 case AML_WHILE_OP: 285 286 ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "[WHILE_OP] Op=%p\n", Op)); 287 288 ControlState = WalkState->ControlState; 289 if (ControlState->Common.Value) 290 { 291 /* Predicate was true, the body of the loop was just executed */ 292 293 /* 294 * This loop counter mechanism allows the interpreter to escape 295 * possibly infinite loops. This can occur in poorly written AML 296 * when the hardware does not respond within a while loop and the 297 * loop does not implement a timeout. 298 */ 299 ControlState->Control.LoopCount++; 300 if (ControlState->Control.LoopCount > AcpiGbl_MaxLoopIterations) 301 { 302 Status = AE_AML_INFINITE_LOOP; 303 break; 304 } 305 306 /* 307 * Go back and evaluate the predicate and maybe execute the loop 308 * another time 309 */ 310 Status = AE_CTRL_PENDING; 311 WalkState->AmlLastWhile = 312 ControlState->Control.AmlPredicateStart; 313 break; 314 } 315 316 /* Predicate was false, terminate this while loop */ 317 318 ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, 319 "[WHILE_OP] termination! Op=%p\n",Op)); 320 321 /* Pop this control state and free it */ 322 323 ControlState = AcpiUtPopGenericState (&WalkState->ControlState); 324 AcpiUtDeleteGenericState (ControlState); 325 break; 326 327 case AML_RETURN_OP: 328 329 ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, 330 "[RETURN_OP] Op=%p Arg=%p\n",Op, Op->Common.Value.Arg)); 331 332 /* 333 * One optional operand -- the return value 334 * It can be either an immediate operand or a result that 335 * has been bubbled up the tree 336 */ 337 if (Op->Common.Value.Arg) 338 { 339 /* Since we have a real Return(), delete any implicit return */ 340 341 AcpiDsClearImplicitReturn (WalkState); 342 343 /* Return statement has an immediate operand */ 344 345 Status = AcpiDsCreateOperands (WalkState, Op->Common.Value.Arg); 346 if (ACPI_FAILURE (Status)) 347 { 348 return (Status); 349 } 350 351 /* 352 * If value being returned is a Reference (such as 353 * an arg or local), resolve it now because it may 354 * cease to exist at the end of the method. 355 */ 356 Status = AcpiExResolveToValue ( 357 &WalkState->Operands [0], WalkState); 358 if (ACPI_FAILURE (Status)) 359 { 360 return (Status); 361 } 362 363 /* 364 * Get the return value and save as the last result 365 * value. This is the only place where WalkState->ReturnDesc 366 * is set to anything other than zero! 367 */ 368 WalkState->ReturnDesc = WalkState->Operands[0]; 369 } 370 else if (WalkState->ResultCount) 371 { 372 /* Since we have a real Return(), delete any implicit return */ 373 374 AcpiDsClearImplicitReturn (WalkState); 375 376 /* 377 * The return value has come from a previous calculation. 378 * 379 * If value being returned is a Reference (such as 380 * an arg or local), resolve it now because it may 381 * cease to exist at the end of the method. 382 * 383 * Allow references created by the Index operator to return 384 * unchanged. 385 */ 386 if ((ACPI_GET_DESCRIPTOR_TYPE (WalkState->Results->Results.ObjDesc[0]) == 387 ACPI_DESC_TYPE_OPERAND) && 388 ((WalkState->Results->Results.ObjDesc [0])->Common.Type == 389 ACPI_TYPE_LOCAL_REFERENCE) && 390 ((WalkState->Results->Results.ObjDesc [0])->Reference.Class != 391 ACPI_REFCLASS_INDEX)) 392 { 393 Status = AcpiExResolveToValue ( 394 &WalkState->Results->Results.ObjDesc [0], WalkState); 395 if (ACPI_FAILURE (Status)) 396 { 397 return (Status); 398 } 399 } 400 401 WalkState->ReturnDesc = WalkState->Results->Results.ObjDesc [0]; 402 } 403 else 404 { 405 /* No return operand */ 406 407 if (WalkState->NumOperands) 408 { 409 AcpiUtRemoveReference (WalkState->Operands [0]); 410 } 411 412 WalkState->Operands[0] = NULL; 413 WalkState->NumOperands = 0; 414 WalkState->ReturnDesc = NULL; 415 } 416 417 418 ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, 419 "Completed RETURN_OP State=%p, RetVal=%p\n", 420 WalkState, WalkState->ReturnDesc)); 421 422 /* End the control method execution right now */ 423 424 Status = AE_CTRL_TERMINATE; 425 break; 426 427 case AML_NOOP_OP: 428 429 /* Just do nothing! */ 430 431 break; 432 433 case AML_BREAK_POINT_OP: 434 435 AcpiDbSignalBreakPoint (WalkState); 436 437 /* Call to the OSL in case OS wants a piece of the action */ 438 439 Status = AcpiOsSignal (ACPI_SIGNAL_BREAKPOINT, 440 "Executed AML Breakpoint opcode"); 441 break; 442 443 case AML_BREAK_OP: 444 case AML_CONTINUE_OP: /* ACPI 2.0 */ 445 446 /* Pop and delete control states until we find a while */ 447 448 while (WalkState->ControlState && 449 (WalkState->ControlState->Control.Opcode != AML_WHILE_OP)) 450 { 451 ControlState = AcpiUtPopGenericState (&WalkState->ControlState); 452 AcpiUtDeleteGenericState (ControlState); 453 } 454 455 /* No while found? */ 456 457 if (!WalkState->ControlState) 458 { 459 return (AE_AML_NO_WHILE); 460 } 461 462 /* Was: WalkState->AmlLastWhile = WalkState->ControlState->Control.AmlPredicateStart; */ 463 464 WalkState->AmlLastWhile = 465 WalkState->ControlState->Control.PackageEnd; 466 467 /* Return status depending on opcode */ 468 469 if (Op->Common.AmlOpcode == AML_BREAK_OP) 470 { 471 Status = AE_CTRL_BREAK; 472 } 473 else 474 { 475 Status = AE_CTRL_CONTINUE; 476 } 477 break; 478 479 default: 480 481 ACPI_ERROR ((AE_INFO, "Unknown control opcode=0x%X Op=%p", 482 Op->Common.AmlOpcode, Op)); 483 484 Status = AE_AML_BAD_OPCODE; 485 break; 486 } 487 488 return (Status); 489 } 490